1. Field of the Invention
Embodiments disclosed herein generally relate to a current perpendicular to plane (CPP) type magnetoresistive effect head as a magnetic reproduction head, and a magnetic recording and reproduction device in which the CPP type magnetoresistive effect head is installed.
2. Description of the Related Art
Magnetoresistive effect magnetic heads are used as sensors for reproducing magnetic information recorded on magnetic media in high density magnetic recording devices such as hard disks, and is a part that greatly affects the performance of magnetic recording technology.
In recent years, magnetic reproduction heads are used that use the so-called giant magneto resistive effect (hereafter referred to as GMR), and so on, namely the magnetoresistive effect of a multilayer film in which ferromagnetic metal layers are stacked with nonmagnetic intermediate layers therebetween. The first GMR heads used were the current: in: plane (CIP) type in which an electrical signal flows parallel within the plane of a sensor film. In order to increase the recording density, the tunneling magneto resistive effect (TMR) head and the current perpendicular to a plane giant magneto resistive effect (GMR) head were developed considering the advantage of high output with narrow tracks and narrow gaps, so in recent years TMR heads have become the mainstream in magnetic reproduction heads. Unlike the conventional GMR head, the TMR head and the CPP-GMR head are CPP type heads in which electrical signals flow in the direction perpendicular to the film surface, and this is the major difference from CIP type heads in which the electrical signal flows parallel within the plane of the sensor film.
In order to respond to the demand for even higher density recording in recent years, the effective track width of magnetoresistive sensors has been made narrower, but this has caused the element resistance to increase, the noise to increase, and sensitivity to reduce, and has produced the separate issue that it is difficult to increase the sensitivity. In order to further increase the density three element type magnetic heads have been proposed as shown in FIG. 1.
The magnetic head in FIG. 1 includes a lower shield/electrode layer 101 having two magnetoresistive effect elements 113, 114 disposed thereover. An insulating layer 104 is disposed over the lower shield layer 101 and along a portion of the two magnetoresistive effect elements 113, 114. Over the insulating layer 104, an element side layer 110 is present. The element side layer 110 is also disposed between the two magnetoresistive effect elements 113, 114. A mask pattern 118 is formed over the element side layer, insulating layer 104 and magnetoresistive effect element 113 while an upper electrode forming film 119 is formed over the element side layer 110, insulating layer 104 and magnetoresistive effect element 114. Another insulating layer 104 is formed over the mask pattern 118, exposed element side layer 110 and upper electrode forming film 119. A second upper electrode 120 is then formed over the upper electrode forming film 119 and the element side layer 110. A magnetoresistive effect element 102, magnetic domain control film 117 and upper shield layer 112 are formed thereover.
The advantage of three element magnetic heads is that by producing a magnetic head having several elements whose size is larger than the bit size of the medium, it is possible to read the bit data from the differences of the plurality of signals obtained. Because the element size can be larger than for a single element, noise can be controlled and sensitivity increased.
Each of the elements of the three element type reproduction element can be produced at a size that is larger than the recording bit size, but in order to extract the signal it is necessary to provide wiring layers between the first magnetoresistive effect element and the first magnetoresistive effect element and the second magnetoresistive effect element, the third magnetoresistive effect element. Therefore if terminals are provided, the distance between each element is increased and the distance between shields is increased.
It is an object of the disclosure to reduce the vertical distance between sensors in a three element type reproduction element, to reduce the distance between shields, and to reduce the lead gap.